Generic monster attacks, take 2: "Library of Attacks"

[Coolthulhu]

This got pretty giant. Recreating PR instead of reopening #17679 because it got some giant updates.

Contains the generic melee attacks as in #17679 but also a "library of monster attacks" which works as follows:

• Monster attacks specified in base context (ie. not in a monster) with type "monster_attack" are written down into MonsterGenerator::attack_map
• In monster context, a monster can either request one of the base types ("leap", "bite" etc.) or "monster_attack", which covers library ones
• A monster can request a library type and make inline modifications to it, in case something tiny needs to be changes - for example cooldown
• Due to the limitations of current implementation, nested library types are NOT supported at the moment
• Hardcoded mattacks are wrapped into a structure similar to that of iuse functions
• Monster attack "type" renamed to "attack_type", as "type" is a reserved keyword for init functions
• Old definitions are supported for now, but will cause warnings in test_mode (--check-mods)

For example:

{
    "type": "monster_attack",
    "attack_type": "bite",
    "id": "nibble",
    "move_cost": 10
}
...
{
    "type": "monster",
    "id": "nibblerung"
    ...
    "special_attacks": [ { "id": "nibble" } ]
}

It is also possible to use the array definition ("special_attacks": [ [ "nibble", 2 ] ]).

EDIT: Added a doc: https://github.com/CleverRaven/Cataclysm-DDA/wiki/Monster-special-attacks

[codemime]

Why do you need this include?

[codemime]

This check doesn't work anymore. The core mod is "dda".

[codemime]

This looks like a reinvented optional( ..., translated_string_reader ).

[Coolthulhu]

How to get it without generic factory?

[codemime]

optional() doesn't depend on it.

[DangerNoodle]

I assume this will warrant reporting on #19376 when it is merged, if it changes monster files. @pisskop and @chaosvolt would need to update their mods.

[chaosvolt]

Eh? Sure, I guess. Wait, JSON API? :V

[DangerNoodle]

See issue mentioned by me above, reporting major JSON changes.

[codemime]

mtype is a struct.

[Coolthulhu]

Should be working now.